External compensation for LTPO pixel for OLED display

1. A system comprising:

an electronic display comprising a plurality of pixels, wherein each pixel of the plurality of pixels comprises respective driving circuitry that supplies a respective driving current to a respective light-emitting diode based on a respective program voltage applied to the respective driving circuitry, and wherein the respective driving circuitry generates the respective driving current according to respective pixel current-voltage (I-V) curves that vary from pixel to pixel; and

processing circuitry configured to:

receive image data;

retrieve, from a memory, stored approximations of the respective pixel current-voltage (I-V) curves as defined by a first function and based at least in part on a correction factor comprising a second function that varies its output in response to changes in current values; and

determine a signal indicative of the respective program voltage for each pixel of the plurality of pixels based at least in part on the approximations of the respective pixel current-voltage (I-V) curves and the image data, wherein the approximations of the respective pixel current-voltage (I-V) curves are defined at least partially before receiving the image data.

2. The system of claim 1 , wherein the first function is specific to each pixel of the plurality of pixels and associates a target driving voltage indicated by the image data to the respective program voltage.

3. The system of claim 2 , wherein the first function comprises a linear regression, a power law model, an exponential model, or some combination thereof.

4. The system of claim 1 , wherein the correction factor is specific to a subset of the plurality of pixels.

5. The system of claim 4 , wherein the subset of the plurality of pixels comprises pixels of a spatial region.

6. The system of claim 4 , wherein the subset of the plurality of pixels comprises pixels of a particular color channel.

7. The system of claim 1 , wherein the correction factor is global to all of the plurality of pixels of the electronic display.

8. The system of claim 1 , wherein the respective driving circuitry comprises a transistor.

9. The system of claim 8 , wherein the transistor comprises an oxide thin film transistor.

10. A method for compensating for non-uniformities of an electronic display, comprising:

receiving, using processing circuitry, image data to be displayed on the electronic display;

determining, using the processing circuitry, a target driving signal for a first pixel of the electronic display based at least in part on the image data to be displayed;

applying, using the processing circuitry, a per-pixel current-voltage (I-V) function approximating a current-voltage (I-V) curve of the first pixel to obtain a modified driving signal;

applying, using the processing circuitry, a correction factor to obtain an adjusted driving signal from the modified driving signal, wherein the correction factor comprises a curvature adjustment function that compensates for approximation errors in the per-pixel current-voltage (I-V) function based on the target driving signal to obtain the adjusted driving signal from the modified driving signal; and

causing the electronic display to drive the first pixel based at least in part on the adjusted driving signal.

11. The method of claim 10 , wherein the per-pixel current-voltage (I-V) function comprises a linear regression, a power law model, an exponential model, or some combination thereof, and wherein a variable to be used to define the per-pixel current-voltage (I-V) function is retrieved from a memory after the determination of the target driving signal.

12. The method of claim 10 , wherein the target driving signal is a target driving current, wherein the per-pixel current-voltage (I-V) function uses the target driving current to obtain the modified driving signal, and wherein the modified driving signal comprises a pixel program voltage.

13. The method of claim 12 , wherein the curvature adjustment function is used to determine a voltage difference to apply to the modified driving signal based at least in part on the target driving current to obtain the adjusted driving signal, and wherein the adjusted driving signal comprises an adjusted pixel program voltage.

14. The method of claim 10 , wherein the curvature adjustment function is applied to modified driving signals for pixels in a particular spatial region of the electronic display to reduce non-uniformity relative to another spatial region of the electronic display.

15. The method of claim 10 , wherein the curvature adjustment function is applied to all pixels in the electronic display.

16. An article of manufacture comprising one or more tangible, non-transitory, machine-readable media storing instructions executable by one or more processors of an electronic device, wherein the instructions comprise instructions to:

receive image data to be displayed on an electronic display;

determine a target driving signal for a first pixel of the electronic display based at least in part on the image data to be displayed;

apply a per-pixel current-voltage (I-V) function approximating a current-voltage (I-V) curve of the first pixel to obtain a modified driving signal;

adjust the modified driving signal based at least in part on a regional or global current-voltage (I-V) curvature adjustment function to obtain an adjusted driving signal, wherein the regional or global current-voltage (I-V) curvature adjustment function compensates for an expected approximation error in the per-pixel current-voltage (I-V) function when the first pixel is driven using the modified driving signal to obtain the adjusted driving signal; and

cause the electronic display to drive the first pixel based at least in part on the adjusted driving signal.

17. The article of manufacture of claim 16 , wherein the per-pixel current-voltage (I-V) function comprises a linear regression, a power law model, an exponential model, or some combination thereof.

18. The article of manufacture of claim 16 , wherein the target driving signal is a target driving current, wherein the per-pixel current-voltage (I-V) function uses the target driving current to obtain the modified driving signal, and wherein the modified driving signal comprises a pixel program voltage.

19. The article of manufacture of claim 16 , wherein the regional or global current-voltage (I-V) curvature adjustment function is applied to modified driving signals corresponding to pixels in a particular spatial region of the electronic display.

20. The article of manufacture of claim 16 , wherein the regional or global current-voltage (I-V) curvature readjustment function is applied to modified driving signals for all pixels in the electronic display.